ENH: added empty input test (good practice)
ENH: added empty input test (good practice)

sankhesh/VTK,ashray/VTK-EVM,spthaolt/VTK,johnkit/vtk-dev,spthaolt/VTK,biddisco/VTK,SimVascular/VTK,gram526/VTK,sumedhasingla/VTK,Wuteyan/VTK,collects/VTK,candy7393/VTK,berendkleinhaneveld/VTK,biddisco/VTK,daviddoria/PointGraphsPhase1,aashish24/VTK-old,hendradarwin/VTK,jeffbaumes/jeffbaumes-vtk,sumedhasingla/VTK,cjh1/VTK,daviddoria/PointGraphsPhase1,mspark93/VTK,mspark93/VTK,berendkleinhaneveld/VTK,sankhesh/VTK,sankhesh/VTK,spthaolt/VTK,jmerkow/VTK,johnkit/vtk-dev,keithroe/vtkoptix,jmerkow/VTK,aashish24/VTK-old,aashish24/VTK-old,hendradarwin/VTK,jmerkow/VTK,candy7393/VTK,berendkleinhaneveld/VTK,arnaudgelas/VTK,naucoin/VTKSlicerWidgets,mspark93/VTK,daviddoria/PointGraphsPhase1,keithroe/vtkoptix,sumedhasingla/VTK,naucoin/VTKSlicerWidgets,sumedhasingla/VTK,spthaolt/VTK,msmolens/VTK,sumedhasingla/VTK,sumedhasingla/VTK,collects/VTK,demarle/VTK,aashish24/VTK-old,SimVascular/VTK,demarle/VTK,collects/VTK,daviddoria/PointGraphsPhase1,gram526/VTK,berendkleinhaneveld/VTK,mspark93/VTK,aashish24/VTK-old,mspark93/VTK,sumedhasingla/VTK,jmerkow/VTK,daviddoria/PointGraphsPhase1,sumedhasingla/VTK,msmolens/VTK,collects/VTK,jmerkow/VTK,mspark93/VTK,berendkleinhaneveld/VTK,jeffbaumes/jeffbaumes-vtk,gram526/VTK,hendradarwin/VTK,spthaolt/VTK,arnaudgelas/VTK,keithroe/vtkoptix,naucoin/VTKSlicerWidgets,sankhesh/VTK,arnaudgelas/VTK,sankhesh/VTK,collects/VTK,daviddoria/PointGraphsPhase1,ashray/VTK-EVM,biddisco/VTK,collects/VTK,cjh1/VTK,ashray/VTK-EVM,SimVascular/VTK,hendradarwin/VTK,keithroe/vtkoptix,mspark93/VTK,Wuteyan/VTK,arnaudgelas/VTK,candy7393/VTK,jmerkow/VTK,demarle/VTK,johnkit/vtk-dev,mspark93/VTK,demarle/VTK,Wuteyan/VTK,jeffbaumes/jeffbaumes-vtk,SimVascular/VTK,ashray/VTK-EVM,Wuteyan/VTK,biddisco/VTK,candy7393/VTK,johnkit/vtk-dev,msmolens/VTK,jeffbaumes/jeffbaumes-vtk,spthaolt/VTK,cjh1/VTK,arnaudgelas/VTK,SimVascular/VTK,ashray/VTK-EVM,jeffbaumes/jeffbaumes-vtk,biddisco/VTK,keithroe/vtkoptix,Wuteyan/VTK,sankhesh/VTK,johnkit/vtk-dev,SimVascular/VTK,hendradarwin/VTK,cjh1/VTK,SimVascular/VTK,cjh1/VTK,sankhesh/VTK,msmolens/VTK,johnkit/vtk-dev,ashray/VTK-EVM,gram526/VTK,keithroe/vtkoptix,biddisco/VTK,msmolens/VTK,hendradarwin/VTK,arnaudgelas/VTK,demarle/VTK,gram526/VTK,gram526/VTK,aashish24/VTK-old,gram526/VTK,jmerkow/VTK,candy7393/VTK,candy7393/VTK,berendkleinhaneveld/VTK,biddisco/VTK,SimVascular/VTK,naucoin/VTKSlicerWidgets,berendkleinhaneveld/VTK,Wuteyan/VTK,Wuteyan/VTK,jeffbaumes/jeffbaumes-vtk,demarle/VTK,spthaolt/VTK,gram526/VTK,keithroe/vtkoptix,cjh1/VTK,hendradarwin/VTK,ashray/VTK-EVM,msmolens/VTK,candy7393/VTK,candy7393/VTK,demarle/VTK,demarle/VTK,sankhesh/VTK,ashray/VTK-EVM,johnkit/vtk-dev,msmolens/VTK,keithroe/vtkoptix,jmerkow/VTK,msmolens/VTK,naucoin/VTKSlicerWidgets,naucoin/VTKSlicerWidgets